The present invention relates to crossline generators and in particular to a damping system for a pendulously supported crossline generator and a method thereof.
Pendulously supported crossline generators, such as used in a laser level, are known in the art for producing visible lines used for references in leveling and squaring operations. Criteria for acceptable performance of the pendulously supported crossline generator involve steady state stability of the generated lines on a work surface, such as a wall, as well as the transient time to stop oscillatory motion after the crossline generator is disturbed. This oscillatory motion occurs in two directions. The first is the translation of the horizontal line up and down a vertical plane, and is simply the result of the pendulously support crossline generator pitching or swinging. The second is the translation of the vertical line back and forth about a horizontal plane (i.e., rotational direction), which is caused by the pendulously supported crossline generator rotating. Oscillatory motion in the rotational direction is allowed by the torsional compliance of a suspension member, such as a spring or a wire, used to suspend the crossline generator.
To damping the above-mentioned pitch and rotational oscillatory motions in both the vertical and rotational directions, some prior art laser levels utilized a paddle on the bottom of the pendulously support crossline generator. Submerging the paddle in a pool of silicone fluid provides the desired damping. Although very effective, problems remained in reliably containing the fluid without spilling or migration onto adjacent parts.
In other prior art pendulously support crossline generators, magnetic damping has been used for some time. Magnetic damping has distinct advantages over fluid damping when it comes to practical implementation into the crossline generator. However, to date, most of the concerns with this method centers on magnetic damping not being generally as effective as fluid damping.